【摘要】 利用离体叶片悬滴法,将从重庆烟区采集分离的烟草赤星病菌13个代表株进行了致病力测定,在PDA平板上对其培养性状进行研究。结果表明,不同菌株之间致病力有明显的差异。其中,3株表现较强的致病力,病指为68 6、63 2和61 8;2株表现中等致病力,病指为57 0和55 6;1株表现较弱致病力,病指为22 9;5株表现弱致病力,病指为4 9、5 6、9 7、14 6和4 8;不致病的有2株,病指为0,未发现有强致病力菌株。通过不同菌株对离体叶片的穿透生长能力与致病力以及病菌来源说明,病菌对离体叶片的穿透生长能力与致病力有一定的一致趋势;在不同的烟区中存在着致病力不同的菌株,同一烟区中也存在着致病力不同的菌株。在培养性状上,13个代表菌株同以往报道的相一致,菌株致病力的强弱与其生长量和产孢量有一定的关系。更多还原

【Abstract】 The pathogenicity for 13 strains of Alternaria alternata were studied,which were collected and isolated from different regions in Chongqing,were used to inoculate the detached leaves with suspension liquid and cultured properties were studied on PDA.The pathogenicity differentiation was shown by severity of the brown spots.Of the strains studied,3 appeared to be relatively powerful virulence,with a disease index of 686,632 and 618,respectively;2 were moderately virulence,with a disease index of 570 and 556,respectively,one showed relatively weak virulence,with a disease index of 229,5 were weak virulence,with disease indexes of 49,56,97,146 and 48,respectively,the other 2 were nonvirulent,and the most virulent strain was not found.The results indicated the ability of penetrating detached leaves and growth and their pathogenicity had a certainly common trend.The strains differing in pathogenicity existed in different tobaccogrowing area,and even strains with different virulence were found to be present in the same plot.The cultured properties of 13 strains were the same as that of the other reported strains,and the pathogenicity of strains was found to be related to their performance under cultured conditions. 更多还原